Various molecular switches have been developed within the past several years. The molecular switches are characterized by having two stable states which can be interchanged with one another. Exemplary molecular switches include redox-active catenanes, redox-active rotaxanes, and redox-active pseudorotaxanes. The molecular switches can be, for example, materials which can be interchanged between two stable states by oxidation and reduction. The oxidation and reduction of a material can be accomplished by, for example, altering a voltage that the material is exposed to.
In referring to this disclosure and the claims which follow, a preferred exemplary switchable material is referred to as a “molecular switchable memory material”, with the term “memory” emphasizing that the material has at least two stable and interchangeable states. It is possible that a memory material can have more than two stable states, but generally it is preferred that the material have only two stable states accessible in the particular environment that the material is utilized in. For instance, a material having multiple stable states accessible through redox reactions can be utilized in an environment wherein a voltage to the material is controlled such that only two of the stable states are accessed during utilization of the material as an active molecular switch.
In theory, the molecular switches can be incorporated into switchable circuit devices. Specifically, one of the stable states of a molecular switch can be referred to as a “1” digital state, and the other stable state can be referred to as a “0”. Accordingly, a circuit device comprising a molecular switch material can be switchable between a first state corresponding to the “0” and a second state corresponding to the “1”. The two states can be utilized for storing memory bits. Additionally, and/or alternatively, one of the stable states of a switchable molecular material can be referred to as an “on state” and the other as an “off state,” and the material can be utilized to control electrical flow within a circuit. Specifically, when the material is in the “on state” electrical flow can proceed through the circuit, and when the material is switched to the “off state”, electrical flow can be stopped within the circuit.
Various difficulties are encountered in attempting to incorporate switchable molecular materials into working circuits. Among the difficulties is that the switchable molecular material can be destroyed when incorporated into the circuit, and accordingly will no longer act as a molecular switch. For purposes of interpreting this disclosure and the claims that follow, an “active’ molecular switch is defined as a molecule which retains an ability to switch from one stable state to another.
It would be desirable to develop new circuit structures incorporating molecular switches, and to develop new methods of forming circuit structures comprising molecular switches.